The present invention relates to a system for the air-conditioning of the interior of a motor vehicle having an engine cooling circuit which has a water/air heat exchanger and a water/water heat exchanger. The system also includes panel heat exchangers in the interior through which water flows from the water/water heat exchanger.
An example of the above-system type is shown in German Published Unexamined Patent Application No. 3,218,710. In this system, the water/air heat exchanger and the water/water heat exchanger are arranged in two parallel line branches of the cooling-water circuit. This requires separate control devices for the two line branches and separate heat exchangers, and is relatively expensive to construct.
An objective of the present invention is to provide a simplified air-conditioning system that reduces the construction expenses and simplifies the controls.
These and other objectives are achieved by providing in a system of the above-described type a water/air heat exchanger and a water/water heat exchanger which are connected in series. The water/water heat exchanger is downstream of the water/air heat exchanger in the engine cooling circuit, and is arranged between the panel heat exchangers and the water/air heat exchanger.
An advantage of a preferred embodiment of the invention is its very compact design, with only one line branch and only one control device for the cooling water. Since the cooling water first flows through the water/air heat exchanger, it is sufficiently cooled in the water/water heat exchanger to prevent undesirable high temperatures from occurring in the panel heat exchangers.
Another advantage provided by a preferred embodiment is allowing the water/water heat exchanger to be built onto a conventional water/air heat exchanger, without the latter having to undergo considerable conversion.
By arranging an evaporator upstream of the water/air heat exchanger, as provided in a further embodiment of the invention, the panel heat exchanger can cool the interior in a simple manner.
The provision of a circulating pump between a return pipe and a feed pipe leading to the water/air heat exchanger aids the flow of cooling water between the two heat exchangers, especially when they are separated from the remaining engine cooling-water circuit, for example under cooling conditions.
Further objects, features and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawings, which show for purpose of illustration only, an embodiment constructed in accordance with the present invention.